NVIDIA Geforce 8400GS Overclocking Guide

Few months back we had a peak at the GeForce 8400GS and we saw how performance wise this card is not that bad of a choice considering its price. Even with that narrow 64-bit bus we could greatly improve the performance of our test samples, but we do feel that there is quite some left in those cards, could we double our framerates with more volts supplied?

Introduction & Tools overview

Introduction

Last year we had a peak at the GeForce 8400GS and we saw how performance wise this card is not that bad of a choice considering its price. Even with that narrow 64-bit bus we could greatly improve the performance of our test samples, but we do feel that there is quite some more performance left in those cards. Voltages are kept rather low for the chosen components, for example the GPU got less then 1,3V to get its work done properly, and while this reduces the power consumption and heat level it also lowers the overclocking headroom for the overclockers out there. Madshrimps is going once again through the voltmodding research, hope goes out for much higher clock speeds while keeping the overclocking process as simple as possible, this mod should be as easy as possible to duplicate by our readers.

From all the samples we went through previously; let us first have a look at which one will serve us best in our overclocking adventure:

The highest scaling shaderclock is of no concern, in time we wrote the 8400GS article we had no access to unlinked shaderclocks, therefore it is XFX who takes the lead because it comes with overclocked shader processors out of the box. But what is interesting is the second sample we received from Albatron, this 8400GS managed to scale well past 650MHz on the GPU core where others had problems getting anything over 600MHz stable. Besides that, Albatron also went for the Hynix DDR2 DRAM which seem to be the better overclocking chips around. With only a 64-bit wide bus, memory speed might be the most crucial point to increase the card performance, therefore we would obviously choose for cards that come with Hynix RAM. In the end, Albatron has those chips feed with only 1,93V, with same volt applied as its competitors Albatron would have topped out again in the above chart. Here is our choice:

In this guide we'll be showing you how to increase performance via voltmods, where to solder and what resistor value's you should look out for. But before we go too much in depth, let me list all the things that might be of use in your overclocking adventure:

Tools

RivaTuner- RivaTuner allows us to measure GPU temperatures, check GPU and mem speeds as well as shader clocks and of course overclocking.

FutureMark 3D Mark- Futuremark’s 3DMark application allows us to stress the GPU and check for system stability;

Nibitor- This custom software is created for the sole purpose to edit the BIOS of NVIDIA video cards; which we can use to flash an altered BIOS with higher pre-overclocked values for GPU/MEM/SHADERS.

NVFlash- Time to hook up that old floppy drive (or modify your USB stick) to boot into DOS, as flashing the video card requires a clean “DOS” boot. NVFlash is the application which can write the new BIOS to the video card.

B2 pencil- A simple pencil can be used to increase the voltage fed to the G80 components if the correct bridges are “colored” in.

Soldering tools- We won’t go into much detail on how you should solder, but show you where to solder what. To get up to speed and tune your soldering skills please refer to our soldering guide

Multimeter- Essential piece of equipment to check the voltages once we start increasing them.